1. Field of the Invention
The present invention relates to an imaging apparatus, and more specifically, to an imaging apparatus having an effective white balance control.
2. Description of the Prior Art
A digital camera as an image input device has been used widely spread together with a development of a personal computer in recent years. Especially, the digital camera is used by means of a photographer who has no special techniques, in many cases. Many digital cameras are adapted to set automatically a shutter speed, an exposure, and a focusing corresponding to an object in order to eliminate a failure in photographing.
Moreover, generally a person is used as the object in many cases; there is also a digital camera, which specially equips a person specific set-up mode. An important thing for these digital cameras is how to carry out a white balance control accurately, and a quality of a photographing result is depended on the accuracy of this white balance control.
Two methods have been used for the white balance control of an electronic imaging apparatus generally. The first method is to measure a color of a light source by an external sensor to carry out the white balance control in accordance with the measured color of the light source. The second method is to conduct an extraction of a feature with respect to a color from an output signal of an image pick up device to carry out the white balance control based on the result of the extraction of the feature.
In a conventional electronic imaging apparatus, the detection of a screen feature for the white balance control has been executed with respect to a display range selected as well as an AE. In this case, because the feature is extracted from only within the screen, when most part of the screen is occupied by a skin color such as a portrait photographing, there is a case that a judgment of the color of the light source for the white balance control is miss-judged as a light source having a low color temperature.
Consequently, as the prior art, Japanese Paten Laid-Open Hei 7-284003 discloses that an object area, which conducts processing of AE, AF, and AWB in accordance with an electronic zoom area, is optimized by changing the object area of conducting the processing of AE, AF, and AWB in accordance with a magnification of an electronic zoom. Basically, this prior art is adapted to conduct the processing within the range of the electronic zoom as the object area.
Moreover, in the imaging apparatus including a conversion function of an aspect ratio disclosed in Japanese Patent No. 3278206, an extraction area of a white balance data in accordance with a conversion correction is changed. This is the area correction in accordance with the aspect conversion, and therefore data from an outside of a displayed area are not used for the white balance control.